Despite the sophistication and versatility of modern power tools, even highly skilled craftsmen oftentimes find it difficult to cut a straight line across stock of any substantial width. In most methods, one of the first steps is the scribing of a line across the width of the board, the intent being to follow the path of the line as closely as possible. This method is characterized by several deficiencies. Firstly, when using a pencil or other device which marks the stock, there is a tendency of the line to get gradually thicker as the pencil is drawn across the board. In most instances, the craftsmen manually push the power tool, such as a circular saw, across the stock attempting to follow the path of the line. This is an inaccurate method; it is quite difficult for the operator to follow the line while he is pushing the saw. Also, the operator is sometimes faced with the problem of which side of the line on which to cut, particularly in those areas where the line has thickened. Furthermore, when attempting to split the line directly down the center, he is working with a line thickness of between 1/32 and 1/16 of an inch and even the exercise of ordinary judgment and care is often not sufficient to split the line.
Frequently, there are additional extraneous factors which interfere with the accuracy of the operator. One such factor is the necessity to drag an electrical cord of the power tool along the stock. These cords tend to be of substantial thickness and weight, and as the power tool is pushed or drawn along the stock, an increasingly greater weight of cord must be compensated for by the operator. This additional weight has a tendency to pull the power tool from the desired path.
The prior art has to some extent recognized the existing problems and attempts have been made to utilize the base plate or shoe of the power tool as a follower. The shoe often includes a straightedge parallel to the plane of the cutting blade. Some craftsmen frequently make use of this straightedge to guide the tool by sliding it against a straightedge guide member. This method is an incomplete solution to the problem. The offset between the follower edge and the cutting blade cannot be accurately measured so that a source of inaccuracy is always present.
Other attempts are characterized by complex, expensive and inconvenient to use apparatus. Furthermore, none of the prior art attempts compensate for differences in individual tools. Different units of the same model of a power tool may exhibit slightly varying differences in the distance between the cutting blade and the shoe follower edge. Therefore, there has been a need in the art to provide effective guidance for a power cutting tool, that is convenient to use and permits an efficient use of an operator's time.